I don't usually give them to the chicks although chicks who free range with their mommas probably get them. I toss them out in the yard and watch the bluebirds scoop them up in less than a minute!
(I've got a house of bluebirds that has been in use for the last 5 years! I just heard peeping today! First brood of the year is here. Could be 3-5 of them!--broods this year)